High-throughput screening instruments (or analyzers) are critical tools in the pharmaceutical research industry and in the process of discovering and developing new drugs. High-throughput analyzers are used to assess the efficacy of candidate drug compounds. Dramatic increases in the number of these compounds and in the number of targets against which they may be directed have created a bottleneck in the development of new drugs and a need for analyzers that can operate with a high degree of analytical 5flexibility and speed. Analytical flexibility and speed are necessary because high-throughput applications may involve repeating the same operations hundreds of thousands of times, greatly magnifying even the smallest shortcomings.
Recently, improved sample containers and luminescence assays have been developed to facilitate high-throughput screening. The improved sample containers include microplates, which are generally rectangular containers that include a plurality of sample wells for holding a plurality of samples. Microplates enhance speed by reducing transit time between samples and reduce cost by employing small amounts of reagents. Unfortunately, microplates also have a number of shortcomings. For example, microplates do not conform to any exact standard, so that their size, shape, and construction materials may vary, depending on vendor or batch. In addition, microplates may vary from opaque to transparent, so that analytical approaches developed for some microplates will not work for other microplates. Moreover, preferred microplates may differ, depending on application. Furthermore, microplates may allot only a small volume for each sample, reducing signal and making it easier to spill sample during transit.
The improved luminescence assays include chemiluminescence and various photoluminescence assays. These assays must be conducted on sensitive analyzers, If especially if performed using the small samples held in microplates. Increased sensitivity is particularly important for chemiluminescence assays, in which the amount of light generated by a sample may be quite small. These assays also differ in many respects, so that each may favor a different optical configuration. Consequently, in the high-throughput screening field, photoluminescence and chemiluminescence assays often are performed separately, using dedicated instruments.